This application relates to, among other things, connection systems for high voltage electrical distribution or reticulation. It finds particular, but not sole, application to the provision of a quick disconnect system to facilitate creating physical disconnect points for maintenance. One example application is for creating physical disconnect points in substations for maintenance.
Electrical substations are part of an electricity generation, transmission, and distribution system. Substations switch generators, equipment, and/or circuits or lines in and out of a system as well as transforming voltage, stepping it up or down depending on the type of substation.
An important part of substations is busbars. Electricity going through the substation is passed through these busbars to be distributed to the individual “bays” within the substation. Power lines from the different substation bays are then connected to the busbars to draw or supply power.
Often isolation of a substation bay is required to perform maintenance or fault repair, which requires the power line to the bay be disconnected from the busbar to cut the electricity to the bay (e.g., promoting a safe working environment for the technicians). In other words, the bay needs to be in a de-energised, or placed in a non-live state for maintenance or work.
Electricity entering the bay during manual operation, such as when technicians are performing maintenance or work, poses serious health and safety risks. Therefore regulations for substation operation often require creating a visible “physical break” in the power line connection to the bay from the busbars before work on the bay can begin. This means there needs to be a visible disconnection or break in the power line connecting the bay to the busbar to ensure no electricity can enter the bay from the busbars.
Currently, expensive technologies exist to provide visible and physical electrical disconnection between the busbar and the bays. These devices are commonly called “high voltage isolators” or “high voltage disconnectors” and are generally three phase gang operated, although they may be single phase.
In recent years, a new technology called Disconnecting Circuit Breakers (DCB) has been introduced by some equipment manufacturers. These devices provide on load electrical disconnection between the busbar and the bays and include an integral earth switch. DCB's do not include the facility to provide an electrical disconnection with a visible physical break. To achieve a visible physical break high voltage/high current connectors must be removed from the DCB's to affect the disconnection.
Should a bay need to be disconnected using these high voltage/high current connectors, a significant number of man hours are required to perform this task. Power companies wish to minimize the downtime (e.g., the period of time during which electricity is cut off) and cost for maintenance or repair works.
In the past, various connectors have been proposed for connecting earthing wires or taps to elongate conductors. These connectors typically comprise a hook portion which cooperates with a jaw portion to secure the connector to the conductor. The jaw portion is typically tightened against the conductor by a threaded member such as a bolt. Removal of the connector from the conductor requires the bolt to be undone, usually with an insulated tool known as a “hot stick”. This procedure can be difficult, as the conductor is typically at a substantial height, and the head of the bolt may be in an unfavourable orientation for engagement with the hot stick, which may be difficult to maneuver due to its length and weight. In addition, the connector may be free to rotate relative to the conductor, particularly once the clamp has been partially loosened. This may make the disconnection operation time consuming and potentially hazardous.
In this specification, where reference is made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.